Knives



Sept. 23, 1969 ARMELIN ET AL 3,468,203

KNIVES Filed April 3. 1967 2 Sheets-Sheet 1 I NVENTORS W ewall ATTORNEYSSept. 23, 1969 ARMEUN ET AL 3,468,203

KNIVES Filed April 3. 1967 2 Sheets-Sheet f2 FIG.4.

INVENTORS amb, kimgup 4 1 0) AT TORNEYS United States Patent ice KNIVESEdouard Roger Armelin, London, and Arthur Frederick George Plaslrett,Orpington, England, assignors to Societe dEtudes de Machines Speciales,a French company Filed Apr. 3, 1967, Ser. No. 627,978 Claims priority,applicatligu6 Great Britain, Apr. 15, 1966,

rm. Cl: B26d 4/48 US. Cl. 83-433 Claims ABSTRACT OF THE DISCLOSURE Thisinvention relates to improvement in knives which are primarily intendedfor cutting flexible web materials such as paper and cardboard.

It is frequently desired to slit a roll of such flexible web materiallongitudinally to form a plurality of further rolls of reduced widths.In order that this may be done, the web is unwound from an existingroll, slit as desired and rewound on to a new spindle in a series ofnarrower rolls.

In some instances it is desirable to slit the'web material withoutapplying counter pressure against the slitting knife by the use of acounter knife. In such cases if a clean slit of the material is to beobtained over the whole length of the web material it has been essentialto maintain a razor edge on the knife, and while it has been known touse knives which can be removed and sharpened as necessary, it has beenfound that this is essential more frequently than is desirable,particularly when slitting relatively strong or abrasive materials.

It is therefore an object of this invention to provide a cutting knifewhich remains effective for much longer usage than hitherto.

In order that this may be done, the slitting knife, which is adapted tobear on the web material during, or prior to, the rewinding operation,is provided with a vibrator. This vibrator may be actuated by forinstance an electric pulse generator in order to vibrate the cuttingedge of the knife at a sufliciently high frequency to cause the materialof the web to disintegrate in the immediate vicinity of contact betweenthe knife cutting edge and the web material, by virtue of one or morefactors, alone or in combination; these factors being (a) the contact ofthe cutting edge with the web material; (b) the impact of the knifecaused by the vibrations; (c) the friction caused by the vibratingknife; and (d) the heat generated at the cutting edge by the vibrations.

If desired, the slitting knife may also be provided with an auxiliaryheater for raising the temperature of the cutting edge in order toassist in the disintegration or slitting of the web at the point ofcontact.

According to the invention there is provided apparatus for slittingflexible web material comprising a cutting edge, means for passing a webto be slit past said cutting edge in contact therewith and means forvibrating said cutting edge at a frequency in the sonic or ultrasonicrange.

According to a further aspect of the invention there is provided amethod of slitting flexible web material comprising progressivelyunwinding a roll of said material, causing the web material to contact acutting edge which 3,468,203 Patented Sept. 23, 1969 is vibrating at afrequency in the sonic or ultrasonic range and rewinding said webmaterial into a plurality of separate rolls of narrower width.

Two embodiments of the invention will now be described by way of exampleonly with reference to the drlawvlilngs accompanying the provisionalspecification in w 1c FIGURE 1 is an end view of one embodiment;

FIGURE 2 is a sectional view on line 2-2 of FIG- URE 1;

FIGURE 3 is an end view of a second embodiment; and

FIGURE 4 is a sectional view on line 4--4 of FIG- URE 3.

Referring initially to FIGURES l and 2, there is shown a supportingframework 20 having a rotatable spindle 2 supporting a roll 1 of webwhich is to be slit and rewound as two separate rolls 3, 4 on a furtherspindle 5 which may be driven by means such as an electric motor (notshown) to rewind the web.

In order to slit the web material 21 a knife 6 having a cutting edge 22is spring-loaded so as to bear tangentially on the web material 21 andslit it into the two rolls 3 and 4 as it is rewound under the cuttingedge 22 onto the spindle 5. The knife 6 is pivoted at pivot point 7 onthe framework 20 and rigidly connected to a loading lever 23 which isattached to an anchored tension spring 8 in order to retain and load thecutting edge 22 in contact with the web 21. If desired any suitablemeans (not shown) may be incorporated in the anchorage of the spring 8,or otherwise, to adjust the pressure between the knife and the web.

The knife 6 is also provided with a vibrator 9' attached to the knifeand actuated by a suitable pulse generator. The pulse generator 24 maybe of any convenient form but must be capable of vibrating the knifeabout its pivot 7 at a frequency in at least the sonic range, althoughultrasonic frequencies in excess of 20,000 c.p.s. are preferable. Onsuch suitable form is an electronic multi-vibrator capable of generatingsquare wave electric pulses, which may be set to any desired frequencyoutput. If desired however, a simpler mechanical pulse generator may beused to vibrate the knife.

In operation, the web of flexible material 2 1 is rewound from the roll1 onto spindle 5, the web 21 passing under the cutting edge 22 to dividethe reel 1 into rolls 3 and 4. In order to slit the web material 21cleanly and to maintain the cutting edge 22 effectively sharp, the knifeis vibrated at a frequency preferably in excess of 20,000 c.p.s. by thevibrator 9, thus causing the web material 21 to part under the action ofthe factors hereinbefore recited. This vibration extends the life of thecutting edge considerably and renders it more effective even when itwould be too blunt to use were no vibrations applied to it. If desired,for certain relatively strong or tough materials, an auxiliary heater(not shown) attached to the knife may be employed to raise thetemperature of the cutting edge to aid the slitting operation.

Turning to FIGURES 3 and 4, there is seen a similar arrangement, wherebya framework 20 supports spindles 11 and 15 from which the roll 10 is tobe rewound and divided into rolls 13 and 14 after passing over a supportroller 12 under a cutting knife 16 again provided with a vibrator 18actuated by a pulse generator 24. In this instance, the support roller12 is provided with an inset groove 25 beneath the knife 16 to allowvibrations of the cutting knife to take place without damaging thecutting edge on the support roller 12 thereof. In this embodiment,furthermore, the cutting knife 16 is firmly clamped by one end 30 on theframework 20 and is constrained to vibrate within a fixed arc dictatedby the depth of the groove 25 in the roller 12, bending along its lengthresiliently, as an alternative to being spring-loaded about a pivot asin the previous arrangement.

In alternative embodiments of the invention a plurality of knives may beused dependent upon the number of final rolls of material that it isdesired to obtain.

We claim:

1. Apparatus for slitting flexible web material comprising: a framework,a web supply spindle and a Web take-up spindle rotatably supported bythe framework, means for driving the web take-up spindle to unwind theweb from the web supply spindle and rewind it into the form of a reel onthe web take-up spindle, a knife for slitting the web as it is woundonto the web take-up spindle, said knife being pivotally mounted on saidframework and being resiliently biased to bear tangentially on the reelof the web on the take-up spindle, and means for vibrating the knife ata frequency at least in the sonic range.

2. Apparatus as claimed in claim 1, wherein said resilient bias isadjustable.

3. Apparatus for slitting flexible web material comprising: a framework,a web supply spindle and a web take-up spindle rotatably supported bythe framework, means for driving the web take-up spindle to unwind theweb from the Web supply spindle and rewind it onto the web take-upspindle, a support roller for said web, said support roller beingrotatably mounted in said framework in the path followed by the web whenbeing rewound onto the web take-up spindle, a cutting edge for slittingthe web, said cutting ede being mounted on the framework and arranged tobear on the web as it passes over the support roller, and means forvibrating the cutting edge at a frequency at least in the sonic range.

4. Apparatus as claimed in claim 3, wherein the sup port roller isprovided with a groove inset therein to allow said cutting edge tovibrate without contacting said support roller.

5. Apparatus as claimed in claim 4, wherein the cutting edge is formedon a knife which is clamped at one end on said framework and which bendsresiliently when vibrated.

References Cited UNITED STATES PATENTS 2,530,134 11/1950 Taylor et a1.3,264,923 8/1966 Waitzman 83427 JAMES M. MEISTER, Primary Examiner U.S.Cl. X.R. 83-5 82

